The candidate must have passed in mathematics in 10+2 examination from a recognized board.

Inclusion of one language from list A is necessary and any 3 of the best subjects from list B is compulsory.  So, Inclusion of economics in best 4 is compulsory but mathematics is not compulsory.

You can refer to the link given below for more information on the inclusion and calculation of best 4 subjects in BA Hons Economics and various other courses.

https://university.careers360.com/articles/du-eligibility-criteria

Hope this helps!